Open educational resources (OER) are teaching and learning materials that are less expensive than commercial course materials. Previous findings have indicated that learning outcomes are similar between OER and commercial resources (which typically require fees to access), but there is considerable variation in the findings. It is not well known which students in what kinds of courses may have different outcomes with OER use. Two characteristics that are important to examine because they are becoming more commonplace in higher education and may struggle with social integration are nontraditionally-aged (age 25 and older) and online students. The purpose of this study is to examine how student age and course modality may vary how OER adoption relates to course grades, withdrawal, and number of credits enrolled in a given semester. To address this purpose, a dataset from seven public postsecondary institutions with 8,033 students was analyzed. Based on multilevel modeling findings, traditionally-aged students had higher grades with OER whereas OER did not reliably relate to the grades of nontraditionally-aged students. However, nontraditionally-aged students in face-to-face courses with OER had greater enrollment intensity (number of credits in a term). OER was not associated with withdrawal rate. Future directions are suggested, which include a need to consider instructor effects and directly hearing student voices on OER experiences.